| ??? 03/17/12 20:31 Read: times |
#186758 - Mirrors or multiple beams - still extremely cheap Responding to: ???'s previous message |
Damir Tadic said:
I was thinking about solution cheaper than industrial photoelectric sensor, devices like this http://www.balluff.com/Balluff/u...ensors.htm
Maybe solution is 3-4 IR LED / phototransistor pairs? One IR beam will not detect smaller object. So use whatever number of beams you need. The cost for each beam is still extremely (!) low. Or make it more interesting by bouncing the same light beam multiple times between mirrors before you detect it. If you do not know the material, you can't play with capacitance or magnetic sensors. Optical sensors can often be used even for transparent objects - because the transparent objects tends to reflect and refract, thereby stealing the beam. If the object may be transparent, you could consider having beams in multiple directions - for example three sets of beams at 60 degree angle. That would make it very hard for a transparent object to pass through all three sets without reflecting or refracting away any of the beams. |
